The present invention is directed to wheel hubs for bicycles and, more particularly, to a wheel hub that is capable of housing both a generator mechanism and a brake force adjusting mechanism.
A conventional bicycle hub comprises a hub axle detachably and nonrotatably mounted in a bicycle fork (frame), a tubular hub shell (outer shell) rotatably mounted on the hub axle, and bearings for rotatably supporting the hub shell on the hub axle. A pair of external hub flanges are formed at the two ends of the hub shell to allow wheel spokes to be attached to the hub shell.
It is known to provide generator mechanisms inside such hub shells to convert rotational power of the hub shell into electrical power for illumination purposes. Incorporating such generator mechanisms into the hub shell provides higher generation efficiency and reduces wheel rotation loss in comparison with generators that contact the wheel rim to convert rotational power of the wheel rim into electrical power. It is also known to mount a brake to the hub for restricting the rotation of the hub shell relative to the hub axle. In some such systems the interior of the hub shell may accommodate an anti-lock brake mechanism (brake force adjusting mechanism) capable of adjusting the damping force of the brake. The brake force adjusting mechanism may use a clutch so that, when considerable brake damping force is applied, the clutch is caused to slip to prevent excessive damping force from being exerted on the wheel. Wheel locking thus can be prevented by adjusting the brake force adjusting mechanism to accommodate the characteristics of the bicycle.
In known systems, the hub shell contains either a generator mechanism or a brake force adjusting mechanism, but not both. It would be convenient to combine such power generating and brake force adjusting functions in a single bicycle wheel. However, attempts to endow a single wheel with both these functions result in the use of two bicycle hubs, each provided with one of the aforementioned functions and configured such that a pair of left and right hub flanges provided at the two ends of the hub shell are attached to wheel spokes in the manner described above. For this reason, adopting one of the hubs as the bicycle hub makes it impossible to attach the other bicycle hub and leaves no choice but to select either the generating function or the brake force adjusting function.
Another convenient feature would be a bicycle frame with a brake for restricting the relative rotation of the hub shell and the hub axle of a bicycle hub when this hub shell contains a generator mechanism. A structure in which the hub shell and the structural members constituting the brake are directly or indirectly connected together is commonly adopted for brake mounting, and meshing mechanisms are often adopted for such connection. When a meshing mechanism is adopted in this manner, appropriate materials and hardening treatments must be selected for the entire hub shell, thus resulting in higher manufacturing costs.
The present invention is directed to a bicycle hub wherein both a generator mechanism and a brake force adjusting mechanism are disposed within the hub shell. The present invention also is directed to a bicycle hub that accommodates both a generator mechanism and an optional brake mechanism.
In one embodiment of the present invention directed to a bicycle hub wherein both a generator mechanism and a brake force adjusting mechanism are disposed within the hub shell, a bicycle hub includes a hub axle and a hub shell including a first tubular member having a first hub flange secured thereto and a separate second tubular member having a second hub flange secured thereto. Bearings are disposed between the hub shell and the hub axle for rotatably supporting the first tubular member and the second tubular member relative to the hub axle. A generator mechanism is housed in the first tubular member and adapted to generate electricity by rotation of the first tubular member relative to the hub axle, and a brake force adjusting mechanism is housed in the second tubular member and adapted to limit a maximum damping force of a brake. In a more specific embodiment, the generator mechanism includes an inside stator retained to the hub axle and an outside rotor that rotates in response to rotation of the first tubular member. Furthermore, the brake force adjusting mechanism includes a brake force receiving member rotatably mounted relative to the hub axle for receiving a braking force from a brake mechanism and a frictional coupler for forming a frictional link between the second tubular member and the brake force receiving member. If desired, the frictional coupler may include a first frictional member nonrotatably coupled relative to the brake force receiving member, a second frictional member nonrotatably coupled relative to the second tubular member in a facing arrangement with the first frictional member, and a biasing mechanism for biasing the first frictional member and the second frictional member toward each other.
In an embodiment of the invention that accommodates both a generator mechanism and an optional brake mechanism, a bicycle hub includes a hub axle and a hub shell including a first tubular member having a first hub flange secured thereto, a separate second tubular member having a second hub flange secured thereto, and a brake coupling member for coupling the second tubular member to a brake device. In this embodiment, the second tubular member is harder than the first tubular member. Bearings are disposed between the hub shell and the hub axle for rotatably supporting the first tubular member and the second tubular member relative to the hub axle, and a generator mechanism is housed in the first tubular member and is adapted to generate electricity by rotation of the first tubular member relative to the hub axle. If desired, a brake force adjusting mechanism adapted to limit a maximum damping force of a brake may be housed in the second tubular member. The structure of the generator mechanism or brake force adjusting mechanism may be similar to the corresponding mechanisms noted above, or they may be different depending upon the application.